### 1 · POST /message:send
POST /a2a/rest/message:send HTTP/1.1
Host: localhost:41241
A2A-Version: 1.0
Content-Type: application/a2a+json

{
  "message": {
    "messageId": "48f165d5-7b00-47f4-b81e-f86f5c8cc1ab",
    "role": "ROLE_USER",
    "parts": [
      {
        "text": "Run the unit tests for payments-api at commit 9f3c2e1"
      }
    ]
  }
}

HTTP/1.1 200 OK
Content-Type: application/a2a+json

{
  "task": {
    "id": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
    "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
    "status": {
      "state": "TASK_STATE_COMPLETED",
      "message": {
        "messageId": "722a91ae-18d4-44c4-84a5-94ba73685d3a",
        "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
        "taskId": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "1 failed, 11 passed"
          }
        ]
      },
      "timestamp": "2026-10-06T09:00:06.000Z"
    },
    "history": [
      {
        "messageId": "48f165d5-7b00-47f4-b81e-f86f5c8cc1ab",
        "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
        "taskId": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
        "role": "ROLE_USER",
        "parts": [
          {
            "text": "Run the unit tests for payments-api at commit 9f3c2e1"
          }
        ]
      },
      {
        "messageId": "43c01fc6-0420-49c3-bc96-d0b839234665",
        "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
        "taskId": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
        "role": "ROLE_AGENT",
        "parts": [
          {
            "text": "Checking out 9f3c2e1 and starting the suite"
          }
        ]
      }
    ],
    "artifacts": [
      {
        "artifactId": "test-log",
        "name": "test-log.txt",
        "parts": [
          {
            "text": "collected 12 items\n"
          },
          {
            "text": "tests/test_charges.py ........  [ 66%]\n"
          },
          {
            "text": "tests/test_refunds.py ..F.  [100%]\n"
          },
          {
            "text": "FAILED tests/test_refunds.py::test_partial_refund - AssertionError: 450 != 500\n"
          },
          {
            "text": "1 failed, 11 passed in 4.21s\n"
          }
        ]
      },
      {
        "artifactId": "summary",
        "name": "summary.json",
        "parts": [
          {
            "data": {
              "passed": 11,
              "failed": 1,
              "failures": [
                {
                  "test": "tests/test_refunds.py::test_partial_refund",
                  "error": "AssertionError: 450 != 500"
                }
              ]
            },
            "mediaType": "application/json"
          }
        ]
      }
    ]
  }
}

### 2 · GET /tasks/{id}
GET /a2a/rest/tasks/bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3?historyLength=0 HTTP/1.1
Host: localhost:41241
A2A-Version: 1.0

HTTP/1.1 200 OK
Content-Type: application/a2a+json

{
  "id": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
  "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
  "status": {
    "state": "TASK_STATE_COMPLETED",
    "message": {
      "messageId": "722a91ae-18d4-44c4-84a5-94ba73685d3a",
      "contextId": "41c0d462-fed8-4f6b-8569-6c9afe9497c3",
      "taskId": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
      "role": "ROLE_AGENT",
      "parts": [
        {
          "text": "1 failed, 11 passed"
        }
      ]
    },
    "timestamp": "2026-10-06T09:00:06.000Z"
  },
  "artifacts": [
    {
      "artifactId": "test-log",
      "name": "test-log.txt",
      "parts": [
        {
          "text": "collected 12 items\n"
        },
        {
          "text": "tests/test_charges.py ........  [ 66%]\n"
        },
        {
          "text": "tests/test_refunds.py ..F.  [100%]\n"
        },
        {
          "text": "FAILED tests/test_refunds.py::test_partial_refund - AssertionError: 450 != 500\n"
        },
        {
          "text": "1 failed, 11 passed in 4.21s\n"
        }
      ]
    },
    {
      "artifactId": "summary",
      "name": "summary.json",
      "parts": [
        {
          "data": {
            "passed": 11,
            "failed": 1,
            "failures": [
              {
                "test": "tests/test_refunds.py::test_partial_refund",
                "error": "AssertionError: 450 != 500"
              }
            ]
          },
          "mediaType": "application/json"
        }
      ]
    }
  ]
}

### 3 · GET /tasks/{id}: not found
GET /a2a/rest/tasks/00000000-0000-4000-8000-000000000000 HTTP/1.1
Host: localhost:41241
A2A-Version: 1.0

HTTP/1.1 404 Not Found
Content-Type: application/a2a+json

{
  "error": {
    "code": 404,
    "status": "NOT_FOUND",
    "message": "Task not found",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_FOUND",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "00000000-0000-4000-8000-000000000000"
        }
      }
    ]
  }
}

### 4 · POST /tasks/{id}:cancel: already completed
POST /a2a/rest/tasks/bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3:cancel HTTP/1.1
Host: localhost:41241
A2A-Version: 1.0
Content-Type: application/a2a+json

{}

HTTP/1.1 400 Bad Request
Content-Type: application/a2a+json

{
  "error": {
    "code": 400,
    "status": "FAILED_PRECONDITION",
    "message": "Task cannot be canceled",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "TASK_NOT_CANCELABLE",
        "domain": "a2a-protocol.org",
        "metadata": {
          "taskId": "bbfb9ea5-50ea-4441-b991-2a8ba0d6f3f3",
          "state": "TASK_STATE_COMPLETED"
        }
      }
    ]
  }
}